1. Field of the Invention
The present invention encompasses a protein designated TADG5 comprising an SH3 domain, a TADG5 DNA segment coding for the TADG5 protein, chimeric cells comprising the TADG5 DNA segment, vectors and plasmids comprising the TADG5 DNA segment and methods for producing the TADG5 protein as well as methods for using the TADG5 protein.
2. Description of the Related Art
Proteins containing SH3 domains have been previously identified. For example, chimeric protein tyrosine kinases comprising SH3 and SH2 domains are disclosed in U.S. Pat. No. 5,439,819. Proteins possessing SH2 and SH3 domains have been found to be important in cell cycle processes, especially in signal transduction pathways. Cyclin-dependent kinases possessing SH3 domains are well known participants in signal transduction processes. SH2 domains interact specifically with various proteins containing phosphotyrosine residues, whereas SH3 regions bind guanine nucleotide releasing factors, believed to be involved in important signaling pathways. The role in signal transduction of numerous molecules possessing SH3 and SH2 domains are discussed by Koch et al. (Science 252:668-674 (1991)).
Interfering in the intracellular signal transduction pathways provides mechanisms for numerous therapeutic applications. While several proteins have been identified that interfere with various signal transduction mechanisms, novel proteins involved in signal transduction pathways are important to provide alternatives for therapy and drug development. The novel protein of the invention provides a heretofore unknown molecule which binds to the promoter region of a number of important genes and the Epstein-Barr virus.
A partial DNA sequence called HSU618 has 95% homology over approximately 560 nucleotides to the TADG5 gene (GenBank Accession No. U61837; submitted by F. Xu from the University of Southern California). The HSU618 sequence does not contain an open reading frame, and instead, contains stop codons in all reading frames. The sequence does, however, exhibit high homology with the TADG5 gene starting at nucleotide 87 of the TADG5 sequence through approximately base 654. HSU618 is indicated to have the capacity to bind cyclin G proteins. Because the HSU618 fragment lacks an open reading frame, it cannot be expressed to produce the corresponding protein fragment, nor could it be said to suggest the TADG5 protein amino acid sequence nor to disclose the isolated and purified DNA segment coding for the TADG5 protein.
The prior art is deficient in lack of the nucleotide and amino acid sequence of the SH3 domain-containing TADG5 protein. The present invention fulfills this long-standing need and desire in the art.